The present invention relates to a magnetic disk apparatus and, more particularly, to a contact type magnetic disk apparatus which performs recording/reproduction in sliding contact with a magnetic disk medium.
Recently, in the field of information storage files, recording density has steadily been increased. One of important factors for achieving high-density recording in a magnetic disk apparatus is to decrease the spacing between a magnetic head and a magnetic disk medium holding writing and reading information.
To decrease the spacing between the magnetic head and the magnetic disk medium, a so-called contact type magnetic disk apparatus in which the magnetic head performs recording/reproduction in sliding contact with the surface of a magnetic disk medium is proposed in H. Hamilton, "CONTACT RECORDING ON PERPENDICULAR RIGID MEDIA", Journal of Magnetic Society of Japan, Vol. 15, Supplement, No. S2 (1991), pp. 483-490, and WO 93/14495.
In such a contact type magnetic disk apparatus such as disclosed in Japanese Patent Laid-Open No. 5-54578, the magnetic head slider is slid in contact with the magnetic disk medium having a liquid lubricant layer formed on its surface. By balancing the attraction arising from the surface tension of the liquid lubricant and the repulsion due to the pressure of the liquid lubricant, the magnetic head slider is caused to slightly float and is held in a noncontact state with respect to the magnetic disk medium, eliminating any damage or destruction resulting from the contact sliding.
In the conventional magnetic disk apparatus described above, however, the loading force of the magnetic head slider needs to be set small in order to prevent damage of the magnetic head slider and the magnetic disk medium. If small projections exist on the magnetic disk medium, or worn powder is deposited on the magnetic disk medium, the noncontact state of the magnetic head slider on the surface of the magnetic disk medium becomes unstable. The magnetic head slider cannot smoothly follow the recording surface of the magnetic disk medium.
More specifically, the magnetic head slider bounces on the magnetic disk medium. In this situation, high-density recording is interrupted, and the output value of a reproduction signal undesirably varies.